I have most of my FX (Phase 90, Chorus, M5, Carbon Copy Delay) all before the preamp. The only thing in my amp's loop is a second M5 for 90% of my delays. It is all controlled by a Ground Control Pro and RJM Rg-16 switcher via MIDI. The loop is set to series and I have tried adjusting the level via the loop controls. No luck. Anytime Loop 5 (the M5 for delay) is engaged there is a slight yet noticeable volume boost. It happens with any delay model. The only real solution I have found so far would be to add a Line Boost to the amp's loop and have it engage anytime I am in a non delay setting to even out the level. I did not think it was very noticeable until I was playing out and had a great monitor mix with my guitars in it. I hit a big A chord and halfway thru it ringing out I engaged the M5 and I could hear the very noticeable jump in volume. It's not like a huge, smack you in the face boost, but it is enough that our sound guy mentioned it. I do know that the manual for the Bogner says "If the effect has "level" switches, set them to "+4". Not sure what the level is coming out of the M5.Hope that helps.

I found a fix for now. I purchased an EH Signal Pad and placed it immediately after the output of the M5 (in the loop for the delays) and turned the output down just a notch with the Pad. Works great. It does effect the depth of the delays a bit but it's better than the boost that was there. It'll work until I can get my hands on an Eventide Timefactor. Thanks for the help I guess.

It sounds like its the level of the effects loop on your amp, especially by the way described it. I had the same problem with my VOX effects loop, but in the end I liked the boost because I wanted my effects to be more noticeable then my regular tone, if it gets too out of line I would just roll down the guitar volume a touch. Although glad to see that you found a solution that worked for you.